1. Field of the Invention
The invention relates to controlling hydrocarbon emissions diffusing from a throttle body through an air path of an air induction system after engine shut-off.
2. Background Art
Partial Zero Emission Vehicle (PZEV) standards have been enacted to provoke automotive manufacturers into producing environmentally friendly vehicles. These standards set more stringent hydrocarbon emission requirements.
To meet these new more stringent hydrocarbon vapor emission requirements, especially for internal combustion engines, a reduction of the amount of hydrocarbon vapor emissions from all sources may be reviewed. Particularly, the diffusion of hydrocarbon vapor emissions through an air induction system after engine shut-off.
Hydrocarbon vapor emissions are adsorbed with carbon materials. For example, slurring is a process where carbon is arranged within a watery mixture for surface coating conduit walls of the air induction system.
Slurring methods, and the like, are expensive processes, particularly when applied inside conduits or as an extra step in the manufacturing of the air induction system. Moreover, the slurring substances applied with the carbon tend to become brittle and break off into the air induction system, which can cause particles and other items to travel through the throttle body and into the engine.